This invention relates to an electrically powered selfmobile apparatus and method for operating the same and, more particularly, to such an apparatus and method for use in mining operations and the like.
There are a number of environments and circumstances under which it is highly desirable to use electrically powered vehicles and self-mobile machines, rather than those powered by internal combustion engines. For example, in operating such vehicles and machines in enclosed spaces such as sub-surface mines, warehouses, holds of ships, etc., it would be desirable to utilize electric power so as to avoid the poisonous gases and other combustion products of internal combustion engines. There also are circumstances and locations where electrical power is available at much more economical rates than equivalent amounts of liquid fuels. However, for such equipment which is too large to be efficiently powered by rechargeable batteries, this requires the provision of a continuous connection to external electrical power.
There are certain types of large earth handling and mining equipment in common use in which the wheels of the equipment are powered by large electric motors, with the required current being generated by on-board generators powered by internal combustion engines. Efficiencies in manufacturing costs, and economies of operation could be achieved if this equipment also could be provided with a continuous connection to remote electrical power so as to eliminate the need for on-board generators.
Various attempts have been made in the past to provide continuous power connections to mobile machinery and vehicles. See, for example, U.S. Pat. Nos. 4,108,264; 3,986,572; 3,695,377; 3,533,483; 3,412,819; 1,733,242 and 1,473,206. As shown in these prior art references, a principal problem to be overcome in providing continuous power connection to such mobile equipment which does not run on tracks, or in fixed patterns, is the method of handling a flexible power line so as to keep it from being run over or damaged by the equipment, interfering with other operations in the vicinity of the equipment, etc. Various attempts to accomplish this result have included automatic cable take-up devices, overhead guide wires for suspending a flexible cable, sliding electrical contacts to overhead wires, and in U.S. Pat. No. 1,733,242, even hydrogen filled balloons for suspending a flexible cable in the air. Limitations in each of these heretofore has prevented wide application of this technology.
It is accordingly the primary object of the present invention to provide an improved method and apparatus for supplying continuous electrical current to electrically powered mobile equipment of the type used for mining, earth moving, agriculture, materials handling, and similar purposes.
Another object is to provide such method and apparatus in which the mobile equipment has 360 degree freedom of movement and may back, turn, and generally operate freely without danger of fouling or damaging the power line to which it is connected.
Another object is to provide such a method and apparatus in which the operator of the mobile equipment or machine may move the machine and power connection apparatus throughout a very large area without the assistance of other personnel or equipment.
These and other objects and advantages of the invention will become apparent from the following detailed specification of preferred embodiments of the invention read in conjunction with the attached drawing .